JPH0882379A - Valve - Google Patents

Abstract

PURPOSE: To prevent a valve body from malfunction owing to a pressure fluctuation, to smooth movement of a valve body, and to improve responsiveness by a method wherein the first pressure receiving area for a pressure, exerted in a slide direction on the road side, of a valve body is made equal to the second pressure receiving area for a pressure, exerted in a slide direction on the independent space part side, thereof. CONSTITUTION: A valve body 35 is slidably located in a disposing space part 38 formed in a valve housing 2 and an independent space part 46 is partitioned in the disposing space part 38. A valve body 35 is reciprocated in the disposing space part 38 through operation of a step motor 4 and an input port 56 connected to the disposing space part 38 is formed in the valve housing 2 in such a manner to cross the slide direction of the valve body 35 and an output port 57 is formed in the valve housing 2 on the slide direction of the valve body 35. The first pressure receiving area S1 on the input port 56 side of the valve 35 is made equal to an input pressure receiving area S2 on the independent space part 46 side to improve responsiveness of the valve body 35.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a valve which opens and closes a valve by causing a valve body to reciprocate linearly in the valve housing by the operation of an actuator.

[0002]

2. Description of the Related Art In recent years, with the development of car electronics, motor driven valves using a motor having a mechanism for converting rotational motion into linear motion have been used to drive intake and exhaust valves. For example, as a system for reducing harmful components such as NOx in exhaust gas discharged from an automobile engine, an exhaust gas recirculation (hereinafter referred to as EGR) system for recirculating exhaust gas containing unburned gas to an intake system is available. is there. As an EGR valve used in this EGR system, one having a structure shown in FIG. 7A is known (for example, Japanese Patent Laid-Open No. 4-231661).

In this EGR valve, a step motor 92 constituting a motor portion is fixed downward to an upper end portion of a valve housing 91 constituting a valve portion via a connecting cover 94. The valve housing 91 is the input port 9
4a and output port 94b, and step motor 92
The shaft 96 has a bearing 97 at a position facing the output shaft 95 of the
Is supported so as to be slidable in the axial direction. A valve body 98 is fixed to the tip of the shaft 96, and the valve body 98 is reciprocally moved by the shaft 96 to provide a valve seat 100 provided in the passage 99.
It is possible to approach and separate from.

A female screw 102 is formed inside the rotor 101 of the step motor 92, and a male screw 103 that is screwed into the female screw 102 is formed on the proximal end side of the output shaft 95. A stopper pin 95b is fixed to the base end of the output shaft 95, and a stopper 101a engageable with the stopper pin 95b is provided at the end of the rotor 101 so as to project.

As shown in FIG. 7 (b), the output shaft 95 is cut into a D-shaped section on the tip side from the position where the external thread 103 is formed, and the D-cut section 95a has the same cross-sectional shape as the D-cut section 95a. The oil-impregnated bearing 104 having the hole 104a is slidably inserted and is non-rotatably supported. The output shaft 95 is reciprocated in the sliding direction as the rotor 101 rotates forward and backward.

A first coupling 105 is fixed to the lower end of the output shaft 95, and a second coupling 108 is fixed to the upper end of the shaft 96.
The output shaft 95 and the shaft 96 are connected by engaging with each other. Both couplings 105, 10
A coil spring 97 is interposed between the two shafts, and both couplings 105 and 108 can be slightly moved in the vertical direction against the biasing force of the coil spring 97. or,
A coil spring 109 that urges the coupling 108 toward the valve housing 91 is interposed between the housing 110 of the step motor 92 and the second coupling 108.

Therefore, in the state shown in FIG. 7A, the coil 111 of the step motor 92 is excited to rotate the rotor 101 in one direction. At this time, the output shaft 95 is the oil-impregnated bearing 10.
The output shaft 95 linearly moves in the step motor 92 because the output shaft 95 is supported so as not to be rotated by the motor 4. Therefore, the valve body 98 has the valve seat 100.
And the input port 94a and the output port 94b are in communication with each other.

On the contrary, the coil 111 of the step motor 92
Is excited to rotate the rotor 101 in the other direction. At this time, the output shaft 95 linearly moves in the protruding direction outside the step motor 92. Therefore, the valve body 98 comes into contact with the valve seat 100, and the input port 94a and the output port 94b are blocked (closed).

[0009]

By the way, the input port 94a is connected to an exhaust system of an engine (not shown) so that exhaust gas from the exhaust system is always supplied.
The output port 94b is connected to the intake system of the engine. Therefore, when the valve body 98 contacts the valve seat 100 and the input port 94a and the output port 94b are partitioned, the input port 94a has a higher pressure than the output port 94b due to the exhaust pressure of the exhaust gas.

Here, the valve body 98 contacts the valve seat 100,
When the input port 94a and the output port 94b are cut off, the exhaust pressure of the exhaust gas at the input port 94a increases due to, for example, operation of the exhaust brake.
The exhaust pressure may be higher than the force of the step motor 92 pressing the valve body 98. Then, the valve body 98 separates from the valve seat 100 by the gas pressure of the exhaust gas, and the input port 9
4a and the output port 94b are communicated with each other. Therefore, there is a problem that the exhaust gas flows from the input port 94a to the output port 94b even though the valve body 98 blocks the input port 94a and the output port 94b.

The lower surface of the valve element 98 receives the exhaust pressure of the exhaust gas at the input port 94a. Therefore, when the valve body 98 is operated and brought into contact with the valve seat 100, the valve body 98 cannot be smoothly moved by the exhaust pressure. Therefore, there is a problem that the responsiveness of the valve body 98 deteriorates.

As a countermeasure against the above, the pressing force of the valve body 98 against the valve seat 100 is increased by increasing the size of the actuator (step motor 92) for operating the valve body 98 or increasing its performance to generate high torque. However, if the actuator cannot be increased in size, it is necessary to reduce the area of the lower surface of the valve body 98 that receives the exhaust pressure. Then, the connection hole 100 of the valve seat 100
Since a becomes small, the flow rate of the exhaust gas flowing from the input port 94a to the output port 94b is throttled by the connection hole 100a, and a predetermined amount of exhaust gas is output.
There is a problem that it cannot be flowed to b.

Further, when the valve element 98 cannot be operated by the actuator, the valve element 98 is moved to the valve seat 10 in order to prevent the exhaust gas from flowing back to the intake system.
There is also a demand to make sure that the input port 94a and the output port 94b are cut off by making contact with 0. Also, set the valve to E
When the valve body 98 cannot be operated by the actuator depending on the application when it is used for other than the GR system, the valve body 98 is separated from the valve seat 100 to ensure the input port 94a and the output port 94b. There is also a demand for communication.

The present invention has been made to solve the above problems, and a first object of the present invention is to prevent the valve body from receiving a force due to a pressure fluctuation and thereby malfunctioning, and to smoothly operate the valve body. (EN) A valve capable of improving responsiveness and smoothly flowing a predetermined amount of fluid.

A second object is to provide a valve capable of operating the valve element in a desired direction to perform an opening operation or a closing operation when the valve element cannot be operated by the actuator. is there.

A third purpose is EG for recirculating exhaust gas.
When used in an R system, it prevents the valve element from operating due to exhaust pressure of the exhaust gas, operates the valve element smoothly to improve responsiveness, and allows a predetermined amount of exhaust gas to flow smoothly. To provide a valve capable of

A fourth object is to provide a valve capable of operating the valve body by the exhaust gas to perform the closing operation when the valve body cannot be operated by the actuator.

[0018]

In order to solve the above-mentioned problems, the invention according to claim 1 provides a valve body sliding chamber formed in a valve housing, and a sliding body provided in the valve body sliding chamber. A valve body that forms an independent space in the valve body slide chamber, an actuator that reciprocates the valve body in the valve body slide chamber, and a valve housing that is orthogonal to the sliding direction of the valve body. A first passage formed and connected to the valve body sliding chamber; and a second passage formed in the valve housing in the sliding direction of the valve body and connected to the valve body sliding chamber. A valve provided with a connection means for connecting the second passage and an independent space portion, the first pressure receiving area of pressure acting in the sliding direction of the valve body on the second passage side, and the independent space. Of the pressure acting in the sliding direction of the valve body on the side
The point is that the pressure receiving area is made equal.

According to a second aspect of the present invention, a first pressure receiving area for pressure acting in the sliding direction of the valve body on the second passage side,
The gist is that the second pressure receiving area of the pressure acting in the sliding direction of the valve element on the side of the independent space is different.

The gist of the invention according to claim 3 is that the valve is used in an exhaust gas recirculation system for returning exhaust gas from the exhaust system to the intake system. In the invention according to claim 4, the first pressure receiving area of the pressure acting in the sliding direction of the valve body on the second passage side and the second pressure receiving area of the pressure acting in the sliding direction of the valve body on the independent space side. Different from the area,
The gist is that the valve body is slid using the exhaust pressure of the exhaust gas so that the valve body blocks the first and second passages.

[0021]

According to the invention described in claim 1, the valve body is slidably provided in the valve body slide chamber formed in the valve housing, and by this valve body, an independent space is provided in the valve body slide chamber. Parts are formed. The valve element is reciprocated in the valve element slide chamber by an actuator. Further, the valve housing is formed so that a first passage orthogonal to the sliding direction of the valve body is connected to the valve body sliding chamber. A second passage that is connected to the valve body sliding chamber is formed in the valve housing in the sliding direction of the valve body. Further, the second passage and the independent space portion are connected by the connecting means. Furthermore, the first pressure receiving area on the side of the second passage that causes the valve element to act in the sliding direction is equal to the second pressure receiving area on the side of the independent space that causes the valve element to act in the sliding direction. Then, when the valve element is slid by the actuator, the first and second passages are communicated with or cut off from each other.

With the valve body blocking the first and second passages, the connecting means equalizes the pressure in the second passage and the pressure in the independent space. Then, the force applied to the first pressure receiving area that acts on the valve body in the sliding direction on the second passage side is equal to the force applied to the second pressure receiving area that acts on the valve body on the independent space portion side in the sliding direction. . Therefore, even if the pressure in the first passage becomes higher than the pressure in the second passage, the valve element does not operate due to the pressure in the first passage. Then, the pressure in the first passage does not give a force for sliding the valve body in the sliding direction. Further, when the pressure in the second passage becomes higher than the pressure in the first passage, the pressure in the independent space portion becomes the same as the pressure in the second passage. Since the first and second pressure receiving areas are equal, no force is applied to slide the valve element in the sliding direction. Further, the pressure in the second passage is equal to the pressure in the independent space. Therefore, when the actuator operates the valve element, the operation can be smoothly performed.
Moreover, the responsiveness of the valve body can be improved, and it is not necessary to make the valve body compact.

According to the second aspect of the present invention, the first pressure receiving area, which receives the pressure that acts on the valve body on the second passage side in the sliding direction, causes the valve body on the independent space side to act on the sliding direction. It is smaller than the second pressure receiving area that receives pressure. In this condition, the actuator slides the valve element to
And communicating the second passage. At this time, if the actuator cannot slide the valve element, the second
Since the force applied to the pressure receiving area is larger than the force applied to the first pressure receiving area, the valve body slides to perform the operation of blocking the first and second passages.

On the contrary, the first pressure receiving area on the second passage side that receives the pressure acting on the valve body in the sliding direction and the second pressure receiving area on the independent space side that receives the pressure acting on the valve body in the sliding direction. Make it bigger. In this state, the valve element is slid by the actuator to connect the first and second passages. At this time, when the actuator cannot slide the valve element, the force applied to the first pressure receiving area is larger than the force applied to the second pressure receiving area, and therefore the valve element slides and the first and second pressure receiving areas slide. The operation of maintaining the state where the two passages are communicated is performed. Therefore, by changing the first pressure receiving area and the second pressure receiving area, the valve body blocks or connects the first and second passages. Therefore, if the magnitude relationship between the first pressure receiving area and the second pressure receiving area is determined according to the usage conditions, the valve body can be moved in a desired direction even when the actuator cannot slide. .

According to the invention of claim 3, the valve body is the first
And, in the state where the second passage is blocked, the pressure of the second passage and the pressure of the independent space become equal by the connecting means. The force applied to the first pressure receiving area and the force applied to the second pressure receiving area are equal. Therefore, even if the pressure in the first passage becomes higher than the pressure in the second passage, or the pressure in the second passage becomes higher than the pressure in the first passage, the valve element does not operate.
Then, even if the pressure in the first passage becomes higher than that in the second passage, the force for sliding the valve element is not applied. Further, the pressure in the second passage is equal to the pressure in the independent space. Therefore, when the actuator slides the valve element, the operation can be smoothly performed with a small force of the actuator. Therefore, it is possible to improve the responsiveness of the valve body, and it is not necessary to make the valve body compact.

According to the fourth aspect of the present invention, the first pressure receiving area and the second pressure receiving area are arranged so that the valve body is slid by the exhaust pressure of the exhaust gas so that the valve body blocks the first and second passages. The area is different. Then, the valve body is slid by the actuator to connect the first and second passages. In this state, even if the actuator cannot slide the valve element, the valve element slides due to the exhaust pressure of the exhaust gas and shuts off the first and second passages.

[0027]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is embodied in an EGR valve will be described below with reference to FIGS.

As shown in FIG. 1, a motor driven valve 1 as an EGR valve comprises a valve housing 2 and a step motor 4 as an actuator mounted on the valve housing 2 via a support member 3. There is.

A support member 3 is mounted on the valve housing 2, and a step motor 4 is mounted on the support member 3. Around the lower surface of the supporting member 3, three cylindrical supporting tubes 5 are integrally formed. A protective cylinder 6 having a cylindrical shape is integrally formed on the lower surface of the support member 3 substantially at the center. A mounting screw 8 is inserted through a flange 7 a formed on the motor housing 7 of the step motor 4 and the support cylinder 5 of the supporting member 3, and the mounting screw 8 is screwed into the valve housing 2. Therefore, the step motor 4 is clamped and fixed to the valve housing 2 via the support member 3. The lower end of the protective cylinder 6 is in contact with the upper surface of the valve housing 2 so that the inside of the protective cylinder 6 is partitioned from the outside.

A circular fitting recess 10 centering on the protective cylinder 6 is formed on the upper surface side of the supporting member 3, and a circular shape having a diameter smaller than that of the fitting recess 10 is formed below the fitting recess 10. A storage recess 11 is formed. A locking step portion 12 is formed on the inner peripheral surface of the lower end of the protective cylinder 6. The rotor 15 of the step motor 4 is provided with a rotating body 17 on which a female screw 16 is formed so as to be integrally rotatable. The rotor 15
The rotating body 17 is rotatably supported by a pair of bearings 18 a and 18 b supported by the motor housing 7. The bearing 18b slightly protrudes from the motor housing 7 and is fitted into the fitting recess 10 of the support member 3.

A pair of exciting coils 20 are arranged on the outer circumference of the rotor 15, and the pair of exciting coils 20 are fixedly attached to the motor housing 7. Therefore, the rotor 15 and the rotating body 17 are rotated by exciting the pair of exciting coils 20.

A male screw 2 is attached to the female screw 16 of the rotating body 17.
The moving body 22 on which 1 is formed is screwed. Mobile 2
An output shaft 23 is inserted in the shaft 2. The lower end of the output shaft 23 is fitted into a rotation stopping member 24 formed in a cylindrical shape. Further, the base end of the shaft 25 is fitted into the rotation stopping member 24.

As shown in FIG. 2, a plurality of protrusions 27 are formed on the outer peripheral surface of the rotation stopping member 24 at equal intervals in the axial direction. Then, it is inserted into the insertion hole 29 of the oil-impregnated bearing 28 arranged in the storage recess 11. Also, oil-impregnated bearing 2
In the insertion hole 29 in FIG.
Is formed, and the protrusion 27 and the engagement recess 30 are engaged with each other.

The projection 27 of the rotation stopping member 24 and the engagement recess 30 of the oil-impregnated bearing 28 are engaged with each other so that the integral rotation of the output shaft 23 and the moving body 22 and the rotor 15 is restricted. Has become. Therefore, the rotation of the rotor 15 causes the output shaft 23 and the shaft 25 to linearly reciprocate in the axial direction. At this time, the detent member 24 is adapted to slide on the oil-impregnated bearing 28. A carbon bearing 32 is disposed on the locking step portion 12 of the protection cylinder 6, and the shaft 25 is slidably inserted therein.

As shown in FIG. 1, the tip of the shaft 25 is inserted into the valve housing 2. A valve body 35 is provided at the tip of the shaft 25. Accordingly, the rotation of the rotor 15 causes the shaft 25 to move in the axial direction, and this movement causes the valve element 35 to reciprocate in the axial direction of the shaft 25. The valve body 35 includes a cylindrical main body 36 and a lid portion 37 formed on the upper end of the main body 36.
It consists of and. The valve housing 2 is provided with a disposing space portion 38 as a valve body sliding chamber for reciprocating the valve body 35 in the axial direction of the shaft 25. A locking step 39 is formed on the inner peripheral surface of the lower end of the installation space 38, and the locking step 39 includes a main body 3 of the valve body 35.
A carbon bearing 40, which slides on the outer peripheral surface of 6, is provided.

Further, a communication hole 41 is formed on the lower surface of the valve housing 2 for connecting the outside with the installation space 38, and a recess 42 is formed between the communication hole 41 and the locking step 39. ing. A seal member 44 is arranged in the recess 42. Further, a female screw (not shown) is formed on the inner peripheral surface of the communication hole 41, and a nut 45 screwed with the female screw is screwed into the female screw. The seal member 44 is sandwiched between the nut 45 and the carbon bearing 40, and the airtightness inside is maintained.

An independent space 46 is formed by the valve element 35, the carbon bearing 40 and the nut 45. A coil spring 47 is arranged in the independent space 46,
The urging force of the coil spring 47 causes the valve element 35 to
Is slid to the step motor 4 side. A restricting portion 50 extending outward is integrally formed on the outer periphery of the upper end of the valve body 35, and the lower surface of the restricting portion 50 engages with the outer periphery of the upper end of the carbon bearing 40 when the valve body 35 moves downward. ing. Further, a contact portion 51 having an arcuate cross section is formed on the upper surface side of the restriction portion 50. A valve seat 52 is arranged at the upper end of the arrangement space 38 so that the contact portion 51 of the valve body 35 comes into contact with and separates from the contact portion 51. The valve seat 52 abuts on the upper side of the abutting portion 51, and a slight gap g is formed between the valve seat 52 and the regulating portion 50.

A circular space recess 55 is formed in the upper portion of the installation space 38. Also, the valve housing 2
Has an input port 56, which is connected to an exhaust system of an engine (not shown) in a direction orthogonal to the sliding direction of the valve element 35 and serves as a first passage through which exhaust gas is supplied. The input port 56 communicates with the disposition space portion 38 via the space recess 55. Therefore, the outer peripheral surface of the main body 36 above the valve body 35 is exposed to the input port 56.

Further, an output port 57 as a second passage connected to an intake system of the engine (not shown) is formed in the valve housing 2 above the valve body 35 that moves in the axial direction of the shaft 25. The output port 57 communicates with the installation space 38 via the valve seat 52.
Therefore, the output port 57 has a lid 37 in the valve body 35.
The upper surface of is exposed. A plurality of connecting holes 58 as connecting means are formed in the lid portion 37, and the output port 57 and the independent space portion 46 are in communication with each other. Further, when the valve body 35 is in contact with the valve seat 52, the input port 56 and the output port 57 are cut off, but the output port 57 is separated from the independent space portion 46 by the connection hole 58. It is connected.

When pressure is applied to the upper surface of the lid portion 37, the valve element 35 is slid downward along the axial direction of the shaft 25. The upper surface of the lid portion 37 serves as a first pressure receiving area S1 that receives a pressure that acts on the valve element 35 in the axial direction. Further, when pressure is applied to the lower surface of the lid portion 37 and the lower end surface of the main body 36 in the independent space portion 46, the valve body 35 is slid upward along the axial direction of the shaft 25. The lower surface of the lid portion 37 and the lower end surface of the main body 36 are the valve body 3
The second pressure receiving area S2 that receives the pressure that causes 5 to act in the axial direction.
Has become. In this embodiment, the first pressure receiving area S1
≈2nd pressure receiving area S2.

Next, the operation of the motor-driven valve 1 constructed as described above will be described. In FIG. 1, the valve body 3
The upper end portion of the contact portion 51 of 5 contacts the valve seat 52 to form a gap g. In addition, the input port 56 by the valve body 35
The output port 57 is cut off from the output port 57. In this state, exhaust gas is supplied to the input port 56 from the exhaust system of the engine (not shown), and the input port 56 has a higher pressure than the output port 57 and the independent space 46 due to the exhaust gas exhaust pressure.

The exhaust pressure of the input port 56 is the valve body 3
The exhaust gas pressure does not move the valve element 35 in the axial direction of the shaft 25, although it is applied to the upper outer peripheral surface of the main body 36 in FIG. Further, although the exhaust pressure is applied to the lower surface of the restriction portion 50, the exhaust pressure also flows into the gap g, and a downward pressure is generated on the upper surface of the restriction portion 50. Since the pressure receiving areas S1 and S2 that receive these pressures are equal, the respective forces are canceled out and the valve body 35 is not moved in the axial direction of the shaft 25.

As a result, even if the exhaust pressure of the input port 56 fluctuates and suddenly rises, the valve element 35 loses the exhaust pressure and slides in the axial direction, so that the input port 56 and the output port 57.
It is possible to prevent and from communicating with each other through the installation space portion 38.

The pressures of the output port 57 and the independent space 46 are the same, and the first pressure receiving area S1 is equal to the second pressure receiving area S2. Therefore, the first and second pressure receiving areas S
The forces applied to 1 and S2 are almost the same. Therefore, the valve body 35
Is not affected by the exhaust pressure of the input port 56.

In this state, in order to connect the input port 56 and the output port 57, the exciting coil 2 of the step motor 4
Excite 0. Then, the rotor 15 is rotated, and as the rotor 15 rotates, a rotational force acts on the output shaft 23 via the female screw 16 of the rotating body 17 and the male screw 21 of the moving body 22.

However, the output shaft 23 is not rotated because the projection 27 of the detent member 24 and the engagement recess 30 of the oil bearing 28 are held in a state in which their rotation is blocked. Therefore, the rotational movement of the rotor 15 is converted into the linear movement of the output shaft 23, and the output shaft 23 and the shaft 25 are moved in the axial direction. At this time, the detent member 24 moves with respect to the oil-impregnated bearing 28, and the shaft 25 moves to the carbon bearing 3
Sliding against 2. Therefore, the valve body 35 moves in the direction away from the valve seat 52 while sliding with respect to the carbon bearing 40, and the valve body 35 separates from the valve seat 52. Therefore, the input port 56 communicates with the output port 57 via the installation space 38, and exhaust gas flows from the input port 56 to the output port 57.

When the valve body 35 is moved in the axial direction of the shaft 25 by the step motor 4 and the input port 56 and the output port 57 are communicated with each other, the first pressure receiving area S1 and the second pressure receiving area S2 are equal to each other. Each pressure receiving area S1, S
The forces received by 2 are equal. Moreover, the exhaust pressure of the input port 56 that slides the valve element 35 in the axial direction is not applied. As a result, even when the exhaust brake is provided and the exhaust pressure of the input port 56 increases due to the operation of the exhaust brake, the valve element 35 can be smoothly slid by the small force of the step motor 4. .

Moreover, since the valve body 35 is not affected by the exhaust pressure of the input port 56, the responsiveness of the valve body 35 can be improved. Further, the step motor 4 can be downsized. Further, for example, when an exhaust brake is provided, even if the exhaust pressure of the input port 56 becomes high due to the operation of the exhaust brake, the valve body 35 slides due to the high exhaust pressure and the input port 56 and Output port 5
It is possible to prevent the communication with 7 from becoming impossible.

Further, even if the pressure receiving areas S1 and S2 of the valve element 35 are large, the valve element 35 can be slid smoothly, so that the valve seat 52 can be enlarged. As a result, the valve seat 52 causes the input port 56 to output port 5
It is possible to supply a predetermined amount of exhaust gas to the output port 57 without restricting the flow rate of the exhaust gas supplied to 7.

Then, the valve element 35 slides, and the input port 5
It is assumed that the step motor 4 breaks down in a state where the 6 and the output port 57 are communicated with each other, and the shaft 25 cannot slide the valve body 35. At this time, the pressures of the input port 56, the output port 57, and the independent space 46 are all equal.

Therefore, the elastic force of the coil spring 47 causes the valve body 35 to slide in the direction of contacting the valve seat 52, and eventually the valve seat 52 and the contact portion 51 of the valve body 35 come into contact with each other to form the input port 56. The output port 57 is cut off. As a result,
Even if the step motor 4 fails and the valve body 35 cannot slide, the valve body 35 operates so as to shut off the input port 56 and the output port 57, so that the exhaust gas from the input port 56 is output. It can be prevented from being supplied to the port 57 and the combustion efficiency of the engine can be prevented from being lowered.

In this embodiment, the valve element 35 is the valve seat 52.
Even when pressure of the input port 56 is applied to the lower surface of the restriction portion 50 in the state of being in contact with the input port 56,
The pressure is applied so that the valve element 35 does not move in the axial direction of the shaft 25.

In addition to this, as shown in FIG.
Is formed to be larger than that of the above-described embodiment, and the lower surface of the restricting portion 50 has an area S4. Due to the restricting portion 50, the area S3 that becomes the second pressure receiving area S2 on the lower surface of the main body 36 is made smaller than that in the above-described embodiment, and the first pressure receiving area S1 and the second pressure receiving area S2
And are different. In this case, when the pressure of the input port 56 increases while the valve body 35 is in contact with the valve seat 52, the area S4 receives the pressure.

Due to this pressure, the valve body 35 tends to move in the direction of contacting the valve seat 52, so that the input port 56 and the output port 57 are reliably shut off. Therefore, the second pressure receiving area S2 is made smaller than the first pressure receiving area S1 to reduce the area S4.
Is formed, and the valve element 35 is positively moved in the direction of contacting the valve seat 52. As a result, it is possible to reliably prevent the valve body 35 from malfunctioning due to pressure fluctuations in the input port 56.

It is also assumed that the valve body 35 cannot be moved due to a failure of the step motor 4 while the valve body 35 is separated from the valve seat 52. In this case, since the force received by the first pressure receiving area S1 is equal to the force received by the areas S3 and S4, the thrust for moving the valve body 35 does not work, but the urging force of the coil spring 47 causes the valve body 3 to move.
5 moves in the direction of contacting the valve seat 52. Therefore, even if the step motor 4 fails, the valve body 35 can reliably partition the input port 56 and the output port 57 to ensure fail-safe operation.

Next, another example of the present invention will be described with reference to FIG. The same members as those in the above-described embodiment are designated by the same reference numerals and detailed description thereof will be omitted. Another example of this is
Similar to FIG. 3, the restricting portion 50 is formed to be larger than that in the above-described embodiment, and the lower surface of the restricting portion 50 has an area S4.
Due to the restriction portion 50, the second pressure receiving area S2 on the lower surface of the main body 36
The area S3 that becomes is smaller than that in the above-described embodiment, and the first pressure receiving area S1 and the second pressure receiving area S2 are made different. In this case, the second pressure receiving area S2 is equal to the lid portion 5 in the independent space portion 46.
7 is an area S3 obtained by adding the area of the lower surface of 7 and the area of the lower surface of the lower end of the main body 36. Further, a space forming step 61 is formed on the inner circumference of the upper end of the carbon bearing 40. The small diameter step portion 60 and the space forming step portion 61 form a space portion 62.
The lower surface of the main body 36 in the space 62 has an area S5.

The space 62 is independent of the space 46 no matter how the valve body 35 slides in the axial direction of the shaft 25.
It does not communicate with the installation space 38. A communication hole 5 is formed in the valve housing 2 and the carbon bearing 40.
9 is formed, and the space portion 6 is formed by the communication hole 59.
2 is always in communication with the outside.

Then, the second pressure receiving area S2 was made smaller than the first pressure receiving area S1, and the area S4 and the space portion 62 were formed to form the area S5. Further, the area S5 in the space 62 is not subjected to the pressure of the input port 56 and the output port 57. Therefore, when the valve body 35 is separated from the valve seat 52, the area S3
And the first pressure receiving area S1 receives a larger force than the force received by the area S4. At this time, the coil spring 47 is easily compressed by the valve body 35.

Now, in the state shown in FIG. 4, the valve element 35 has the valve seat 5
2 and the input port 56 and the output port 57 are cut off. In this state, when the exhaust pressure of the exhaust gas at the input port 56 suddenly rises, the area S4 of the restriction portion 50 receives the exhaust pressure. Therefore, the valve element 35 is further attached to the valve seat 5
Since the valve body 35 slides in the direction in which the valve body 35 comes into contact with the second port 2, it is possible to prevent the valve body 35 from sliding due to exhaust pressure and causing the input port 56 and the output port 57 to communicate with each other. As a result, even if the pressure of the input port 56 fluctuates, it is possible to reliably prevent the valve body 35 from malfunctioning.

In order to make the input port 56 and the output port 57 communicate with each other, the step motor 4 is operated to operate the shaft 2
5 is moved in the axial direction. Then, the valve element 35 moves while sliding in the axial direction of the shaft 25 with respect to the carbon bearing 40. Therefore, the valve body 35 separates from the valve seat 52,
The input port 56 and the output port 57 communicate with each other. Further, although the volume of the space 62 is reduced due to the sliding of the valve body 35,
The air therein is discharged to the outside through the communication hole 59.

Further, it is assumed that the step motor 4 fails and the valve body 35 cannot be slid while the valve body 35 slides and the input port 56 and the output port 57 are in communication with each other. At this time, the input port 56 and the output port 57
And the independent space 46 has the same pressure. However, the pressure of the space portion 62 is the same as that of the atmosphere and is lower than that of the input port 56, the output port 57 and the independent space portion 46. Therefore, since the force received by the first pressure receiving area S1 is larger than the force received by the areas S3 and S4, the valve body 35 slides in the direction further away from the valve seat 52 to compress the coil spring 47. . Then, the regulating portion 50 of the valve body 35 comes into contact with the carbon bearing 40, and the sliding is completed.

Therefore, the second pressure receiving area S2 is made smaller than the first pressure receiving area S1 and the input port 56 and the output port 57 are made.
The space portion 62 that does not receive the pressure is formed. Therefore, when the step motor 4 cannot slide the valve body 35 while the valve body 35 is separated from the valve seat 52,
The valve body 35 can be slid in the direction away from the valve seat 52 to bring the input port 56 and the output port 57 into communication with each other. As a result, the motor driven valve 1
This valve is used for applications other than the GR valve, and when the step motor 4 fails and the valve body 35 cannot be slid, the input port 56 and the output port 57 need to be in communication with each other. Can be applied.

In this embodiment, the lid portion 37 of the valve body 35 is used.
A connecting hole 58 is formed in the output port 57 and the independent space 4
6 and were connected. In addition to this, as shown in FIG. 5, a first connection hole 65 connected to the output port 57 is formed in the valve housing 2, and a second connection hole 66 connected to the independent space portion 46 is formed in the nut 45. . The first and second connection holes 65 and 66 are connected by a connection pipe 67 as a connecting means. With this configuration as well, the output port 57 and the independent space portion 46 can be connected to obtain the same pressure.

Further, another example of this embodiment is shown in FIG. still,
The same members as those in the above-mentioned embodiment or members having the same action are designated by the same reference numerals, and detailed description thereof will be omitted. A cover member 70 that constitutes the valve housing 2 is placed on the upper portion of the valve housing 2 via a seal material 71. A carbon bearing 72 is arranged on the upper surface of the cover member 70, and the carbon bearing 72 slidably supports the shaft 25. An installation space 38 is formed in the valve housing 2 corresponding to the lower surface side of the cover member 70. A locking step 39 is formed on the inner circumference of the upper end of the installation space 38, and the valve element 35 is formed in the locking step 39.
Bearing 40 sliding on the outer peripheral surface of the main body 36 in
Is provided.

An independent space 46 is formed by the valve element 35, the carbon bearing 40 and the cover member 70.
A coil spring 47 is arranged in the independent space 46, and the urging force of the coil spring 47 causes the valve body 35 to slide toward the side opposite to the step motor 4. A valve seat 52 is arranged at the lower end of the arrangement space 38 so that the contact portion 51 of the valve body 35 comes into contact with and separates from the contact portion 51.

A circular space concave portion 55 is formed in the lower portion of the arrangement space portion 38. Also, the valve housing 2
Has an output port 57 as a first passage connected to an intake system of an engine (not shown) in a direction orthogonal to the sliding direction of the valve body 35. The output port 57 is communicated with the disposition space 38 through the space recess 55. Therefore, the outer periphery of the main body 36 of the valve body 52 is exposed at the output port 57.

Further, an input port 56 as a second passage connected to the exhaust system of the engine (not shown) is formed in the valve housing 2 below the valve body 35 where the valve body 35 moves in the axial direction of the shaft 25. There is. The input port 56 communicates with the installation space portion 38 via the valve seat 52. Therefore, the upper surface of the lid portion 37 of the valve body 35 is exposed to the input port 56. The lid 3
7, a plurality of connection holes 58 are formed, and the input port 56 and the independent space portion 46 are in communication with each other. Therefore, when the exhaust gas is supplied to the input port 56 from the exhaust system of the engine, the independent space portion 46 also has the exhaust gas exhaust pressure.

The shaft 25 is inserted into a lid portion 37 of the valve body 35 and is projected on the lower surface thereof. An engaging ring 75 is provided on the shaft 25 protruding from the lower surface of the lid 37, and the engaging ring 75 is engaged with the lid 37. In this case, the first pressure receiving area S1 and the second pressure receiving area S2 are equal.

When the shaft 25 is moved upward by the step motor 4, the engagement ring 75 provided on the shaft 25 causes the valve body 35 to slide upward while sliding on the carbon bearing 40. As a result, the valve element 35 is separated from the valve seat 52, and the input port 56 and the output port 57 are in communication with each other.

Further, in the state where the valve body 35 contacts the valve seat 52 and the input port 56 and the output port 57 are shut off, even if the exhaust pressure of the exhaust gas of the input port 56 suddenly rises, the first pressure reception Since the area S1 and the second pressure receiving area S2 are the same, it is possible to prevent the valve body 35 from sliding and causing the input port 56 and the output port 57 to communicate with each other. Then, the valve element 35 can be slid with a small force of the step motor 4.

Further, if the second pressure receiving area S2 is set to be larger than the first pressure receiving area S1, the pressure applied to the second pressure receiving area S2 becomes larger, so that the valve body 35 contacts the valve seat 52, The state in which the input port 56 and the output port 57 are reliably cut off can be maintained. Moreover, under this condition, the input port 56 and the output port 57 are communicated with each other, and even if the step motor 4 fails, the valve body 35 is slid by the pressure applied to the second pressure receiving area S2, and the valve body 35 is moved to the valve seat 52. The input port 56 and the output port 57 can be blocked by contacting each other.

In this embodiment, the valve element 35 has a cup-shaped cross section, but it may have a columnar shape or a polygonal columnar shape if necessary. Further, the valve body 35 having a polygonal columnar shape can be a cup-shaped cross section. In this case, the weight of the valve body 35 can be reduced and the valve body 35 can be moved smoothly.

In this embodiment, the shaft 25 and the valve body 35 are slid by the step motor 4, but the shaft 25 and the valve body 35 may be slid by a diaphragm type.

Further, in this embodiment, the coil spring 4 is used as a means for urging the valve element 35 toward the valve seat 52.
Although No. 7 is used, a bamboo shoot spring or a bellows-shaped leaf spring may be used instead.

[0075]

As described above in detail, according to the first aspect of the invention, even if the pressure in the first passage becomes higher than the pressure in the second passage, the valve body moves in the sliding direction. I can't give you power. Further, the pressure in the second passage and the pressure in the independent space become equal, and the first and second pressure receiving areas are equal. Therefore, even if the pressure in the second passage becomes higher than the pressure in the first passage, no force for moving in the sliding direction is applied to the valve body. Therefore, even if a pressure difference occurs between the pressure in the first passage and the pressure in the second passage, the valve element does not operate due to this pressure difference. As a result, the state in which the first passage and the second passage are reliably blocked can be maintained. Also, the second
Since the pressure in the passage and the pressure in the independent space are equal and the first and second pressure receiving areas are equal, when the actuator slides the valve element, the sliding is smoothly performed with a small force of the actuator. be able to. Moreover, the responsiveness of the valve body can be improved. Further, even if the valve body is enlarged, the actuator can surely slide the valve body. According to the second aspect of the present invention, when the actuator cannot slide the valve body, the first and second pressure receiving areas are made different from each other to slide the valve body so that the first and second It is possible to maintain the passage of the above in a continuous state, or to keep the first passage and the second passage in the closed state.

According to the third aspect of the invention, even if the pressure in the first passage becomes higher than the pressure in the second passage, the valve body is not provided with a force for moving in the sliding direction. In addition, the pressure in the second passage and the pressure in the independent space become equal, and
And the second pressure receiving areas are equal. Therefore, even if the pressure in the second passage becomes higher than the pressure in the first passage, no force for moving in the sliding direction is applied to the valve body. Therefore, even if a pressure difference occurs between the pressure in the first passage and the pressure in the second passage, the valve element does not operate due to this pressure difference. As a result,
It is possible to maintain the state where the first passage and the second passage are reliably blocked. Further, since the pressure in the second passage is equal to the pressure in the independent space, and the first and second pressure receiving areas are equal, when the actuator slides the valve body, the sliding force can be reduced with a small force of the actuator. It can be done smoothly. Moreover, the responsiveness of the valve body can be improved. Further, even if the valve body is enlarged, the actuator can surely slide the valve body.

According to the fourth aspect of the invention, the first and second pressure receiving areas are made different so that the valve body is slid so as to block the first and second passages by the exhaust pressure of the exhaust gas. . As a result, when the actuator cannot slide the valve body in a state where the valve body is slid by the actuator and the first and second passages are communicated with each other, the valve body slides due to the exhaust pressure of the exhaust gas. Then, the first and second passages are shut off. As a result, even if the actuator fails, the valve element reliably blocks the first and second passages, so that exhaust gas can be prevented from flowing back from the exhaust system to the intake system.

[Brief description of drawings]

FIG. 1 is a sectional view showing a motor-driven valve according to the present invention.

FIG. 2 shows that the output shaft and the shaft are fitted in the rotation stopping member,
FIG. 6 is a partially exploded perspective view showing that the rotation stopping member is inserted into the oil-impregnated bearing.

FIG. 3 is a partial cross-sectional view showing another example in which the shape of the valve body is changed.

FIG. 4 is a partial cross-sectional view showing another example in which the second pressure receiving area is smaller than the first pressure receiving area.

FIG. 5 is a partial cross-sectional view showing another example in which an output port and an independent space portion are connected by a connection pipe.

FIG. 6 is a partial cross-sectional view showing another example in which the arrangement of the valve body is changed.

FIG. 7 (a) is a cross-sectional view showing a conventional motor-driven valve, and FIG. 7 (b) is a cross-sectional view showing a D-cut portion formed on the output shaft, the output shaft being supported by an oil-impregnated bearing. It is a figure.

[Explanation of symbols]

2 ... Valve housing, 4 ... Step motor as actuator, 35 ... Valve body, 38 ... Arrangement space part as valve body slide chamber, 46 ... Independent space part, 56 ... Input as first or second passage Port, 57 ... Output port as first or second passage, 58 ... Connection hole as connecting means, 6
7 ... Connection pipe as connecting means, S1 ... First pressure receiving area, S2 ... Second pressure receiving area

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yuzuru Ikeda 2-chome Toyota-cho, Kariya city, Aichi Prefecture Toyota Industries Corporation

Claims (4)

[Claims] 1. A valve body sliding chamber formed in a valve housing, a valve body slidably provided in the valve body sliding chamber, and forming an independent space in the valve body sliding chamber, An actuator for reciprocating the valve body in the valve body sliding chamber; a first passage formed in the valve housing so as to be orthogonal to the sliding direction of the valve body and connected to the valve body sliding chamber; It is formed on the valve housing in the sliding direction of the valve body,
A valve comprising: a second passage connected to the valve body sliding chamber; and a connection means for connecting the second passage to an independent space portion, wherein the valve body has a second passage side. A valve in which the first pressure receiving area of the pressure acting in the sliding direction and the second pressure receiving area of the pressure acting in the sliding direction of the valve body on the independent space side are equal. 2. A first pressure receiving area of pressure acting in the sliding direction of the valve body on the second passage side and a second pressure receiving area of pressure acting in the sliding direction of the valve body on the independent space side. The valve according to claim 1, which is different. 3. The valve according to claim 1, wherein the valve is used in an exhaust gas recirculation system for returning exhaust gas from an exhaust system to an intake system. 4. A first pressure receiving area of pressure acting in the sliding direction of the valve body on the second passage side and a second pressure receiving area of pressure acting in the sliding direction of the valve body on the independent space side. 4. The valve according to claim 3, wherein the valve element is made different from each other, and the valve element is slid by utilizing the exhaust pressure of the exhaust gas so that the valve element blocks the first and second passages.